"Money also has diminishing marginal utility, so as you accumulate more of it, at some point it has less use."

The additional money does not have less use. It's just not going to add as much to quality of life. There are still many uses for it.

You seem to be interpreting utility in terms of the quantity of things the money can be used for or in terms of the societal benefit that can be obtained from the money, it is not entirely clear.

This thread is in response to this, to point out that the use of money is not the same as the marginal utility. Its mot like having a bunch of money makes it less useful or have fewer uses.

Yes, but as I said above, in this case having use is defined relative to promoting your own satisfaction as a consumer.

I think you are trying to tease apart "utility" vs "use", but to have utility is the property of having use. It's a question of what the utility/use is in reference to, and for economists, that utility is in reference to preference satisfaction by the consumers.